Principles of protein and peptide conformation are being studied by multinuclear high resolution magnetic resonance. Several tetrapeptides are being studied in an attempt to correlate spectral data with predicted conformational data. In particular the propensity of these molecules to assume a beta-turn conformation is being assessed. Protein-Protein interactions are being studied through the use of trypsin and various inhibitors. One protein, the basic pancreatic trypsin inhibitor, is being studied in particular through the introduction of specific 13C labels.